The present disclosure relates generally to a tubing hanger for use with a subsea wellhead, and in particular, a mechanism for sealing a tubing hanger in a subsea wellhead.
Tubing hangers are employed in subsea wellheads used in, for example, oil and gas wells. The tubing hanger supports the tubing, or “string”, which extends down into the production zone of the well. The tubing hanger can be installed in the wellhead at the well location. Tubing hanger installation can be performed by various means, such as, for example, by employing a tubing hanger running tool that positions the tubing hanger into the wellhead. Tubing hangers are generally locked into place in the wellhead in order to reduce undesired movement of the tubing hanger relative to the wellhead.
The annulus between the tubing hanger and the wellhead housing employs a seal barrier. One of the seals that forms such a barrier is a metal seal that often functions by forming a forced contact with the sealing surface on the tubing hanger and wellhead housing.
When a tubing hanger is installed into or removed from a wellhead, seals formed between the tubing hanger and wellhead can sometimes be damaged. For example, during installation of the tubing hanger into the wellhead, seals that form part of the tubing hanger can contact portions of the wellhead through which they pass. The interference of the seal with the wellhead during installation can damage the seal.
Additionally, some tubing hanger designs may rely on the landing and/or locking movement of the tubing hanger relative to the wellhead in order to energize the seals. Such tubing hanger designs can make it difficult for operators to reposition the tubing hanger in the wellhead and/or verify that the tubing hanger is correctly positioned in the wellhead without risk of damaging the seals.
The present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the issues set forth above.